Acute kidney injury (AKI) is a rapid loss of kidney function, which in its severe form, is associated with significant morbidity and mortality. Its causes are numerous and include low blood volume from any cause, exposure to substances harmful to the kidney, and obstruction of the urinary tract. As a result, AKI can be a complication from a surgical procedure, particular cardiac surgery. AKI may lead to a number of complications, including metabolic acidosis, high potassium levels, uremia, changes in body fluid balance, and effects to other organ systems. Management includes supportive care, such as renal replacement therapy, as well as treatment of the underlying disorder, and the effectiveness of treatment of AKI increases greatly with timely diagnosis.